1. Field of the Invention
The present invention relates to apparatus for rotating tubing or a pipestring after assembly of the latter within a wellhead.
2. Description of the Prior Art
Many oil wells are provided with pumps located deep underground, and power sources located above ground. Motion of the power source is transmitted to the pump by reciprocating rods, known in the industry as sucker rods, extending therebetween. Due to the great extent of these sucker rods, they can flex during a stroke, and rub against the inside of the tubing or pipestring in which they are enclosed. This contact will eventually result in localized wear of the pipestring.
The most economical approach to mitigating this problem appears to be rotating the pipestring, so that the contact is spread over a greater area of a portion of tubing. A given section of tubing thus survives far more wear prior to being destroyed thereby. Apparatus for rotating the pipestring of a well is known in the prior art.
U.S. Pat. No. 1,650,102, issued to Sheridan P. Tschappat on Nov. 22, 1927 and U.S. Pat. Nos. 2,599,039 and 2,693,238, issued to Jack F. Baker on Jun. 3, 1952 and Nov. 2, 1954, respectively, disclose devices for rotatably suspending a pipestring in a well. The devices of Baker '039 and '238 cap the well opening and incorporate an antifriction combination radial and thrust bearing. Openings are formed in a portion of the devices for accepting a lever or the like. The lever is used to rotate the devices and tubing attached to the same.
The device of Tschappat '102 also seals a well, having a rubber packing ring and a compression ring, and also has a thrust bearing. Rotation is accomplished by loosening a compression member and applying a wrench to a portion of the pipestring.
The hanger of Baker '039 is turned by inserting a rod or the like through a slot formed in a first member, into a recess formed in another member. One of these members rotates and the other is stationary, so that rotation is limited to an extent dictated by a point past which the recess and slot no longer align.
U.K. Pat. Document No. 959,749, dated Jun. 3, 1964, discloses a slip bowl, which shares certain structural and functional similarities to the housing of the present invention, although substantial differences will become evident upon reference to drawings and description of the latter included hereinafter.
U.S. Pat. No. 2,294,061, issued to Roy C. Williamson on Aug. 25, 1942, discloses a tubing rotating device having a split or two piece handle which is assembled and clamped around a tubing member.
German Patent Document No. 1,131,617, dated Jun. 20, 1962, discloses a ratcheting device for rotating tubing. Further examples of rotating devices are seen in U.S. Pat. Nos. 2,471,198 and 2,595,434, issued respectively to David R. Cormany on May 24, 1949 and to William W. Williams on May 6, 1952.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.